CJK
SILVER Star
@RoaringFork — sooo how do we solve this and stop sucking chum into our turbos??
Wits End Turbo Owners (2 Viewers)
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RoaringFork
SILVER Star
there is really no way around PCV unless you vent it to atmosphere or the exhaust, but that would be against emissions laws…
I would like to see the PCV valve moved or another check valve added closer to the manifold(green circle in pic below)… as pictured boost pressure fills the hoses and catch can, then stops at the PCV(red line)
I would like to see the PCV valve moved or another check valve added closer to the manifold(green circle in pic below)… as pictured boost pressure fills the hoses and catch can, then stops at the PCV(red line)
CJK
SILVER Star
Thanks for the tips and confirming what I found via Google Machine.
I’ll add catch cans to both PCV and breather lines + add a check valve between PCV-side catch can and manifold.
I’ll add catch cans to both PCV and breather lines + add a check valve between PCV-side catch can and manifold.
alia176
SILVER Star
Agree, thank you for the explanation @RoaringFork . The crankcase pressure in this pic is being created by the blowbys from the combustion chambers, yes?
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RoaringFork
SILVER Star
The majority of the crankcase pressure is created by blow by, for any flow circumstance. The difference is where the suction to evacuate the pressure is coming from…
the picture above is describing flow when: the manifold is no longer the source of suction(ie when under boost or open throttle valve). The suction now occurs in the fresh air side. Think of how much fresh air the turbo is drawing in when boosting, that is the suction drawing in the crankcase gas.
I'm curious for those of you having excess oil through the intake tract during boost are you running the factory paper air filter?
I know we all love the OEM paper filter because it cleans better and its Toyota and so on and so forth, but because of the increased restriction you would be seeing higher vacuum through the intake tract then if you had a higher flowing filter. Might be worth a test to see the difference in intake vacuum between the factory filter and some other brand with better flow. The reduced vacuum would pull less air from the breather but if your using a separator it would also slow the velocity giving the oil more time to separate.
Take this with a grain of salt, as it's coming from someone without a turbo who has to live vicariously through you guys until I cobble something together for my unbearably slow pig!
I know we all love the OEM paper filter because it cleans better and its Toyota and so on and so forth, but because of the increased restriction you would be seeing higher vacuum through the intake tract then if you had a higher flowing filter. Might be worth a test to see the difference in intake vacuum between the factory filter and some other brand with better flow. The reduced vacuum would pull less air from the breather but if your using a separator it would also slow the velocity giving the oil more time to separate.
Take this with a grain of salt, as it's coming from someone without a turbo who has to live vicariously through you guys until I cobble something together for my unbearably slow pig!
This is a related thread on the same topic, but for the supercharger:
forum.ih8mud.com
PCV System with the TRD Supercharger
I'm putting in a supercharger and I came across this thread: PCV 101 for Forced Induction 80's Basically, it suggests that the PCV routing should be changed from the TRD instructions so that the PCV hose moves from the intake manifold to the throttle body adapter pre-supercharger...
forum.ih8mud.com
I also copied and do this.This is a related thread on the same topic, but for the supercharger:
PCV System with the TRD Supercharger
I'm putting in a supercharger and I came across this thread: PCV 101 for Forced Induction 80's Basically, it suggests that the PCV routing should be changed from the TRD instructions so that the PCV hose moves from the intake manifold to the throttle body adapter pre-supercharger...
CJK
SILVER Star
Great find and totally makes sense.This is a related thread on the same topic, but for the supercharger:
PCV System with the TRD Supercharger
I'm putting in a supercharger and I came across this thread: PCV 101 for Forced Induction 80's Basically, it suggests that the PCV routing should be changed from the TRD instructions so that the PCV hose moves from the intake manifold to the throttle body adapter pre-supercharger...
If we were sticking with recreating the stock system, it seems to me that breather vent hose belongs hooked up to intake between air filter and pre-turbo breather tube (now used for PCV)
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RoaringFork
SILVER Star
I’m having trouble picturing what you’re describing?
“cap off manifold and move the PCV line to the intake tube”
so both PCV and breather hoses to intake tube? Or eliminate breather hose? How about a visual?
the theory behind 2 hoses is the gasses will always have a source of suction to evacuate: to the manifold when vacuum is present there, or the intake tube when no vac in manifold. Is the vacuum required for proper venting? Probably… so going to 1 hose or only using one source of suction may be an issue.
the biggest difference in the PCV from S/C to turbo is: the location of the throttle valve. S/C: throttle valve before charger, turbo: throttle valve after charger. (Manifold)Vacuum starts at the throttle valve(blue in pic below), boost starts at the charger(yellow). Plumbing the PCV hose to the “post throttle valve, pre charger” port on the t-body as described in the linked thread, the system would operate the same as where it is installed in OEM configuration… because, the port on the t-body is pressurized on with the turbo set up, but is only a source of vacuum on the S/C set up…
CJK
SILVER Star
Ah, yes. So if we were to hook the PCV to Air intake (pre-turbo), it will always be under vacuum and thus gases can always vent there. I’d be concerned of too much vacuum in the crankcase under full boost as the crankcase would always be trying to equalize pressure with intake (vacuum).
So I think the best optionis:
Keep system routing as is.
1) Install check valve at manifold-PCV junction to prevent boost leak pressurizing crankcase
2) Install catch can between PCV Valve and Manifold
3) Install catch can between Breather vent and breather tube at air intake.
this would enable the system to vent properly under both conditions (vacuum in manifold, boost in manifold)
1) vent to PCV-manifold when manifold pressure < 0 PSI with OCC#1 trapping goop
2) vent to air intake when manifold pressure >= 0 PSI with OCC#2 trapping goop
RoaringFork
SILVER Star
The intake tube(pre turbo)is not always under vacuum(when throttle valve is closed, ie idle or deceleration), it is however always open to the breather hose so crankcase venting can happen anytime if that is the path of least resistance.
this is all correct
This has me thinking… the following is speculation only…
the amount of air flow(suction) in the intake tube has drastically increased compared to NA. Meaning the amount of suction on the breather hose has increased, possibly drawing the crankcase into a vacuum or drawing more than normal oil vapor through the hose during heavy load situations. The air flow increase is greater than crankcase pressure increase, so what is the extras suction doing? If anything?
Maybe a restrictor in the breather hose to better equalize suction to crankcase pressure? Or T into the breather hose and hook up a vacuum gauge and do some heavy load runs?
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CJK
SILVER Star
Ugh…buy once, cry once.
I went with 2 Radium OCCs and the PCV OCC has their PCV valve on the outlet.
I’m sure we could make the $20 cans work decently, but seems like several more hours of messing with it. I’d rather dish out the money and be done worrying about it.
Their blog post explained the issue really well with images. Obviously, we have one PCV-Manifold line only
I went with 2 Radium OCCs and the PCV OCC has their PCV valve on the outlet.
I’m sure we could make the $20 cans work decently, but seems like several more hours of messing with it. I’d rather dish out the money and be done worrying about it.
Their blog post explained the issue really well with images. Obviously, we have one PCV-Manifold line only
For what it’s worth, here are two Radium catch cans plumbed. I have probably 2000 miles on them now I’m this configuration. A simple L bracket just stands on an empty fender bolt, and if you whistle out the holes on the Radium bracket provided they actually line up to the Charcoal canister studs. I need to buy some angled fittings to clean routing up, just haven’t sourced any yet.
alia176
SILVER Star
^ that is super clean install, thanks for sharing. So, you have zero oil puddle in the compressor housing after this mod? Could you show us a pic of it opened up, when you get a chance, that is. Thank you for the time.
Where did you buy the catch cans, if I may? Given that these are simply vac hoses, wonder if one could get away with more, thin wall hoses for less "beefy" look and better routing around the firewall?
Although lengths of hoses may contribute to the amount of suction, perhaps and not a good idea.
Where did you buy the catch cans, if I may? Given that these are simply vac hoses, wonder if one could get away with more, thin wall hoses for less "beefy" look and better routing around the firewall?
Although lengths of hoses may contribute to the amount of suction, perhaps and not a good idea.CJK
SILVER Star
^ that is super clean install, thanks for sharing. So, you have zero oil puddle in the compressor housing after this mod? Could you show us a pic of it opened up, when you get a chance, that is. Thank you for the time.
Where did you buy the catch cans, if I may? Given that these are simply vac hoses, wonder if one could get away with more, thin wall hoses for less "beefy" look and better routing around the firewall?
I just ordered this from Radium to throw money at the problem and hope it disappears.
Fumes enter from the top hole and leave the can through the side. Both cans will have 90 deg pushlocks on top so that hose routes well.
Catch can between PCV and Manifold has a PCV Valve on the "exit" from the can.
CJK
SILVER Star
Thanks for sharing these images, I've been looking at how to mount these so this helps.
These are Radium Engineering cans, same as what CJK just ordered up. I’m on the road, currently Utah, but will check for oil pooling when I get a sec and report back. Based on this discussion I may swap the hoses on the passenger can, though Radium’s instructions say you can plumb them either direction.
the absurd amount of hose under the hood bothers me too, and I’m curious how the length of hose affects vacuum etc, but I was in a rush to get these in place after having sonic cleaned the intake. I’ve probably collected 1/4 cup of oil between the two so far. More in the PCV can, but probably 70/30.
the absurd amount of hose under the hood bothers me too, and I’m curious how the length of hose affects vacuum etc, but I was in a rush to get these in place after having sonic cleaned the intake. I’ve probably collected 1/4 cup of oil between the two so far. More in the PCV can, but probably 70/30.
CJK
SILVER Star
Outside of a leak, the only way to lose vacuum is due to frictional forces on the hose.
Longer hose = more surface area --> more frictional losses
Smaller diameter dose = more surface area relative to air column --> more frictional losses
Anecdotally, with 6 ft of hose, I doubt the loss would be noticeable but we should be able to use math to figure it out and confirm/deny.
That makes sense. I think I'll monitor and see how adding a valve right at the manifold helps. I also went down this path because I was noticing oil seeping out of the breather/intake hose connection, so I was definitely pulling oil that direction. Also, for the purists, I did have to mess with the throttle cable routing bracket, angled and bent, to get that can to fit at the charcoal canister. I essentially need several different 90 fittings. One will fit there between the OCC and the power steering res to route that hose back toward the firewall.
Also, apologies my engine is normally cleaner than this 
And if someone is local in Utah or when I'm home in the bay area, they can have my PETG prototype L bracket. I used it for 1000 miles before making a steel version and it held up great. I kinda miss the pink under the hood tbh lol.
Also, apologies my engine is normally cleaner than this
And if someone is local in Utah or when I'm home in the bay area, they can have my PETG prototype L bracket. I used it for 1000 miles before making a steel version and it held up great. I kinda miss the pink under the hood tbh lol.
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